The present invention is directed to a tank treatment assembly and, more particularly, to a treatment unit and fluid treatment system in which a treatment unit is mounted in the tank at its top and/or bottom for treating fluid entering and/or leaving the tank.
A wide variety of fluid treatment systems have been employed in the past in which the fluid is passed through a fluid treatment medium which is contained in some form of container or tank. For example, such systems have included water softening systems in which a bed of particulate ion exchange medium is contained in a water softener tank and the water to be treated is introduced through an inlet valve at the top of the tank, flows by gravity and pressure through the ion exchange medium, and the softened water is removed by way of an outlet or discharge from the bottom of the tank through a riser pipe which also passes through the top of the tank.
In such water softening systems it may frequently be desirable to pretreat the water prior to its passage through the ion exchange medium to remove undesirable constituents which might impair the function or reduce the life of the ion exchange medium or reduce the quality of the finally treated fluid. For example, such pretreatment might include the removal of large particulate contaminants which might ultimately collect in and clog the ion exchange medium. It may also be desirable to remove certain chemical contaminants or other constituents which might impart undesirable flavors and/or odors to the treated water, or which might impair or reduce the life of the ion exchange medium itself, such as chlorine which is frequently present in municipal water supplies. Such pretreatments and/or post treatments generally have been known in the past. For example in Heskett U.S. Pat. No. 5,415,770 it is disclosed that the use of certain finely divided metals, such as alloys of copper and zinc, to pretreat water to remove such chemical constituents, including residual chlorine, prior to subjecting the water to a water softening ion exchange medium is beneficial to prolong the life and function of the ion exchange medium, or may be utilized to post treat the water to remove contaminants which for example produce undesirable odors or flavors which were not removed by the ion exchange medium.
Such prior water treatment systems are subject to several disadvantages. For example, where the treatment medium is a finely divided copper and zinc alloy for the removal of chlorine and other constituents, the treatment unit was frequently located separately from the water softener tank in its water supply line to insure that the volume of the treatment medium and residence time was sufficient to perform its intended chlorine removal purpose and to permit ease of replacement of the treatment medium once it has been spent. If it was desired to locate the finely divided metal treatment medium in the same tank or container as the ion exchange medium to eliminate a tank from the system, it would generally be necessary to provide dividers or other containment to keep the particulate metal medium separate from the ion exchange medium, because they would tend to rapidly intermix with each other due to the disparity in weight between the two media. However, this is typically impossible due to the relatively small tank top opening which would not permit placing the relatively larger diameter dividers in the tank as would be needed, and it would be physically difficult to service or replace one medium without replacing the other due to their positioning relative to each other. If the treatment medium was to be placed in a container that would fit into the relatively small diameter opening in the preexisting tank top, the pressure drop of the incoming liquid would be too great due to the considerably reduced cross-sectional area of the treatment media and increased height for the same volume of media.
It is the purpose of the present invention to avoid and eliminate the aforementioned disadvantages. In the present invention a highly efficient fluid treatment unit is capable of being positioned completely inside the primary water treatment tank, for example a water softener tank, for containing a finely divided treatment medium to either pretreat the water prior to its exposure to the primary treatment medium, or to post treat the water after its exposure to the primary treatment medium, and to prevent intermixing of the two media. Due to the unique construction of the treatment unit of the present invention, it is capable of substantial reduction in size, yet permits full treatment of the incoming or outgoing water and with a minimum of pressure drop. Another advantage of the present invention is that the treatment unit of the invention is capable of mounting in or through the preexisting tank top opening, for example in a water softener tank, as were the prior control valves and mechanisms for operating the softener through its cycles and without reconfiguration or restructuring of the prior tank. Still another advantage of the present invention is that the treatment unit, together with its contained treatment medium, may be readily removed from the tank, serviced, and/or replaced without disturbing the primary medium in the tank. Still another advantage of the present invention is that the treatment medium may readily, thoroughly and effectively be backflushed at the same time and with the same backflushing liquids that are utilized to regenerate and/or backflush the primary treatment medium, for example the ion exchange resin in a water softener. Still another advantage of the pretreatment unit of the present invention is that it is possible to accommodate at least two different liquid treatment media with different backflushing requirements, one in the tank itself which has a much larger cross-sectional area and lower flow rate, for example an ion exchange resin, and the other in the treatment unit which has a much smaller cross-sectional area and higher flow rate, for example the much heavier metal particles as discussed in the aforementioned U.S. Pat. No. 5,415,770. Still another advantage of the present invention is that in some embodiments, several different media may be contained in the treatment unit of the invention. Still another advantage of the treatment unit of the present invention is that it may be wholly or partially submerged in the primary treatment medium, thus maximizing the amount of such primary treatment medium for a given tank size and/or minimizing the size of the tank for a given amount of primary treatment medium.
In one principal aspect of the present invention, a fluid treatment system for treating fluids includes a fluid treatment tank for containing a first fluid treatment medium therein. The tank includes an inlet for introducing the fluid to be treated to the tank, an outlet for discharging the fluid which has been treated by the first medium from the tank and a treatment unit in the tank at the inlet to the tank and positioned to receive the fluid introduced to the tank and pretreat before it is treated by the first medium when the first medium is contained in the tank, or which is positioned at the outlet of the tank to receive and treat the fluid which is being discharged from the tank. The treatment unit includes a chamber having an inner wall and an outer wall which define a space therebetween in the chamber for receiving and containing a second finely divided fluid treatment medium. At least one inlet opening extends through one of the walls of the chamber of the treatment unit for introducing the fluid to be treated to the space and so as to pass through the second medium to be treated thereby. At least one outlet opening also extends through another of the walls of the chamber for discharging the fluid which has been treated from the space, the outlet opening being constructed and arranged relative to the inlet opening to increase the time that the fluid dwells in the chamber during treatment of the fluid to increase the effectiveness of the treatment.
In another principal aspect of the present invention, in the aforementioned system and/or unit the inlet opening is positioned adjacent the top of one of the inner and outer walls, and the outlet opening is positioned adjacent the bottom of the chamber to cause the fluid to flow from the top to the bottom of the space in the chamber to increase the dwell time of the fluid during treatment.
In still another principal aspect of the present invention the outlet opening is positioned either in the bottom wall of the chamber or adjacent the bottom of the other of said inner and outer walls to cause said fluid to flow diagonally through said space to increase the dwell time of the fluid during treatment.
In still another principal aspect of the present invention, the area of the inlet opening is greater than the area of the outlet opening to increase the dwell time of the fluid during treatment.
In still another aspect of the present invention, a plurality of the chambers are arranged relative to each other so that the inlet openings of at least some of the chambers are arranged in parallel flow relationship to each other.
In still another principal aspect of the present invention, at least some of the chambers are also arranged in series to each other, and wherein one of the series chambers includes the inlet opening and another of the series chambers includes the outlet opening.
In still another principal aspect of the present invention, adjacent ones of the chambers are removably attached to each other.
In still another principal aspect of the present invention, a housing surrounds and contains some or all of the chambers, and the housing is constructed and arranged to receive fluid from or deliver fluid to the chambers which it contains.
In still another principal aspect of the present invention, at least some of the chambers are outside of the aforementioned housing and the last mentioned chambers have a given cross-sectional area and diameter; and the remaining chambers are within the housing, the housing has a diameter which is substantially equal to the given diameter, and the remaining chambers have a cross-sectional area which is substantially equal to the given cross-sectional area but an overall diameter which is substantially less than the given diameter to define a fluid flow channel between the remaining chambers and the housing.
In still another principal aspect of the present invention, the inner wall of the chambers defines a channel for the flow of the fluid.
In still another principal aspect of the present invention, in the system of the invention the inlet and outlet of the tank and the inlet of the pretreatment unit are at the top of the tank, the outlet of the tank includes a riser conduit which extends from adjacent the bottom of the tank into the channel of the unit, and the inner wall of the chamber surrounds the riser but is spaced therefrom whereby the channel communicates the fluid to be treated to the inlet openings of the chambers.
In still another principal aspect of the present invention, the system is a water softener system, the first fluid treatment medium is a water softening medium, and control means is provided to periodically reverse the flow of water through the water softening medium and the chambers for regeneration of the water softening medium and backflushing of both the first treatment medium and the second treatment medium.
In still another principal aspect of the present invention, where the system is a water softener system, it includes an adapter for mounting the water softener control means and the pretreatment unit in the top of the tank.
In still another principal aspect of the present invention, the second treatment medium is a finely divided metal alloy of copper and zinc.
In still another principal aspect of the present invention, the treatment unit is a pretreatment unit which is arranged in the aforementioned tank to pretreat the fluid prior to the treatment by the first fluid treatment medium.
In sill another principal aspect of the present invention, the treatment unit is a post treatment unit which is arranged in the aforementioned tank to treat the fluid after the treatment by the first fluid treatment medium.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.